Adding possability to use 64bit unsigned long long in nk_property_ull gui element

[KenthJohan]

Using 32bit size signed is limited to [−2,147,483,647, +2,147,483,647] range.
It's not possible to have larger value than that in the current Nuklear.
Adding support for unsigned long long which is 64bit size will have [0, +18,446,744,073,709,551,615] range and open up more possibility for apps using Nuklear.
The function could be called nk_property_ull(struct nk_context *ctx, const char *name, unsigned long long min, unsigned long long *val, unsigned long long max, unsigned long long step, float inc_per_pixel).

Adding this function would require:

enum nk_property_kind {
    NK_PROPERTY_INT,
    NK_PROPERTY_FLOAT,
    NK_PROPERTY_DOUBLE,
+   NK_PROPERTY_ULL
};

union nk_property {
    int i;
    float f;
    double d;
+   unsigned long long ull;
};

We have to think about not overflowing signed or wrap around unsigned values. INT30-C INT32-C.

[dumblob]

Generally I'm not against 64 (or more) bit widths nor against adding new property functions to Nuklear. I'm though quite concerned about unsigned as all other functions were deliberately signed. Would it work for your use case to use signed 64 bit integers?

There should be also a "friend" function analogous to nk_propertyi().